Where does “राजबंशी” come from?

राजबंशी (Rajbanshi) comes from Sanskrit राजवंशीय — of the royal race.

Ancestry of “राजबंशी”, step by step

Step	Language	Word	Meaning
1	Sanskrit	राजवंशीय	of the royal race

राजबंशी — Etymology, Origin & Word History | Etymology Explorer